Changes in energy Flashcards – AQA GCSE Combined Science: Trilogy (8464) — Physics — Foundation

In $E_p = mgh$, what do $E_p$, $m$, $g$, and $h$ represent, and what are their units?

• $E_p$: gravitational potential energy, joules (J)
• $m$: mass, kilograms (kg)
• $g$: gravitational field strength, newtons per kilogram (N/kg)
• $h$: height, metres (m)

What equation is used to calculate gravitational potential energy?

$E_p = mgh$

What is gravitational potential energy?

The energy an object gains when it is raised above ground level.

Why does increasing speed have a much larger effect on kinetic energy than the same proportional increase in mass?

Because kinetic energy depends on $v^2$: speed is squared, but mass is not.

In $E_k = \frac{1}{2}mv^2$, what do $E_k$, $m$, and $v$ represent, and what units should they be in?

• $E_k$: kinetic energy in joules (J)
• $m$: mass in kilograms (kg)
• $v$: speed in metres per second (m/s)

What is kinetic energy?

The energy an object has because it is moving.

What equation is used to calculate kinetic energy?

$E_k = \frac{1}{2}mv^2$